During
the disintegration of the Western Empire, when heresy was rife and all moral
values were threatened by the barbarian invasions, Pope Leo I stands out as the
resolute champion of the faith. His courage and sagacity lifted the prestige of
the Holy See mightily, and earned for him the title of "The Great," a
distinction bestowed on but one other pope, Gregory I. The Church honored Leo
further with the title of Doctor because of his expositions of Christian
doctrine, extracts from which are now incorporated in the lessons of the
Catholic breviary. Of his birth and early years we have no reliable information;
his family was probably Tuscan. We know that he was at Rome as a deacon under
Pope Celestine I and Pope Sixtus III, whose pontificates ran from 422 to 440.
Leo must have achieved eminence early, for even then he corresponded with
Archbishop Cyril of Alexandria,[1] and Cassian dedicated his treatise against
Nestorius to him.[2] In 440 Leo was sent to Gaul to try to make peace between
the imperial generals, Aetius and Albinus. Soon afterward Pope Sixtus died, and
a deputation came up from Rome to inform Leo that he had been elected to the
chair of St. Peter. His consecration took place in September of that year, and
he at once began to show great energy in the performance of the papal duties.

The new pope set himself to make the Roman church a pattern for all other
churches. In the ninety-six sermons which have come down to us, we find Leo
stressing the virtues of almsgiving, fasting, and prayer, and also expounding
Catholic doctrine with clarity and conciseness, in particular the dogma of the
Incarnation. He was determined to shield his flock from heresy, and when he
discovered that many Manichaeans,[3] who had fled from the Vandals in Africa,
had settled in Rome and were spreading their errors, he summoned them before a
council of clergy and laymen. Under cross- examination some confessed to immoral
practices and some recanted. Against the recalcitrant, Leo invoked the secular
authority; their books were burned, and they themselves were banished or else
left Rome of their own volition. Meanwhile he was preaching vigorously against
the false teaching, as Augustine had done earlier, and writing letters of
warning to all the Italian bishops. One hundred and forty-three letters written
by him and thirty letters written to him have been preserved; they illustrate
the Pope's extraordinary vigilance over the Church in all parts of the Empire.
He also encouraged the bishops, especially the Italian ones, to come to Rome to
consult him in person.

From Spain Turibius, bishop of Astorga, sent Leo a copy of a letter he had
been circulating on the heresy of Priscillianism. The sect had made great
headway in Spain and some of the Catholic clergy favored it. As it developed
there, it seems to have combined astrology and fatalism with the Manichaean
theory of the evil of matter. Leo wrote back a long refutation of this doctrine
and described the measures he had taken against the Manichaeans in Rome. Several
times he was asked to arbitrate affairs in Gaul. Twice he nullified acts of the
saintly Hilary, bishop of Arles, who had exceeded his powers. The Emperor
Valentinian III in the famous edict of 445 denounced the Gallic bishop and
declared "that nothing should be done in Gaul contrary to ancient usage,
without the authority of the bishop of Rome, and that the decree of the
apostolic see should henceforth be law." Thus was the primacy of Rome given
official recognition. One of Leo's letters to Anastasius, bishop of
Thessalonica, reminds him that all bishops had a right to appeal to Rome,
"according to ancient tradition." In 446 he writes to the African
church in Mauretania, forbidding the appointment of a layman to the episcopate,
or of any man who had been twice married or who had married a widow. (I Timothy
iii,2.) The rules which he incorporated into Church law regarding admission to
the priesthood deserve mention: former slaves and those employed in unlawful or
unseemly occupations could not be ordained; to be acceptable, candidates must be
mature men who had already proved themselves in the service of the Church.

Leo was now called upon to deal with difficulties in the East far greater
than any he had so far encountered in the West. In the year 448, he received a
letter from Abbot Eutyches of Constantinople, complaining of a revival of the
Nestorian heresy at Antioch. The next year came a second letter, copies of which
he sent also to the patriarchs of Alexandria and Jerusalem. In this Eutyches
protested against a sentence of excommunication just issued against him by
Flavian, patriarch of Constantinople, and asked to be reinstated. His appeal was
supported by a letter from the Emperor of the East, Theodosius II. As no
official notice of the proceedings at Constantinople had hitherto reached Rome,
Leo wrote to Flavian for his version; with his reply, he sent a report of the
synod at which Eutyches had been condemned. From this it seemed clear that
Eutyches had fallen into the error of denying the human nature of Christ, a
heresy which was the opposite of Nestorianism.

A council was summoned at Ephesus by Theodosius, ostensibly to inquire
impartially into the matter. Actually it was packed with friends of Eutyches and
presided over by one of his strongest supporters, Dioscorus, patriarch of
Alexandria. This gathering, which Leo branded as a Robber Council, acquitted
Eutyches and condemned Flavian, who was also subjected to physical violence. The
Pope's legates refused to subscribe to the unjust sentence; they were not
allowed to read to the council a letter from Leo to Flavian, known later as
Leo's <Tome>. One legate was imprisoned and the other escaped with
difficulty. As soon as the Pope heard of these proceedings, he declared the
decisions null and void, and wrote a bold letter to the Emperor, in which he
said: "Leave to the bishops the liberty of defending the faith; neither
worldly power nor terror will ever succeed in destroying it. Protect the Church
and seek to preserve its peace, that Christ in His turn may protect your
empire."

Two years later, in 451, under a new emperor, Marcian, a greater council was
held at Chalcedon, a city of Bithynia in Asia Minor. At least six hundred
bishops were present. Leo sent three legates. Flavian was dead but his memory
was vindicated; Dioscorus was convicted of having maliciously suppressed Leo's
letters at the Robbers' Council, and of virtually excommunicating the Pope
himself. For these and other offenses he was declared excommunicate and deposed.
Leo's <Tome> of 449 to Flavian was now read by his legates to the council.
In it he concisely defined the Catholic doctrine of the Incarnation and the two
natures of Christ, avoiding the pitfalls of Nestorianism on the one hand and of
Eutychianism on the other. "Peter has spoken by the mouth of Leo!"
exclaimed the bishops. This statement of the two-fold nature of Christ was to be
accepted by later ages as the Church's official teaching. Leo, however, refused
to confirm the council's canon which recognized the patriarch of Constantinople
as primate over the East.

In the meantime, serious events of another kind were happening in the West.
Attila, "the scourge of God," after overrunning Greece and Germany
with his Huns, had penetrated France, where he had been defeated at Chalons by
the imperial general Aetius. Falling back, he gathered fresh forces, and then
entered Italy from the northeast, burning Aquileia and leaving destruction in
his wake. After sacking Milan and Pavia, he set out to attack the capital. The
wretched Emperor Valentinian III shut himself up within the walls of remote
Ravenna; panic seized the people of Rome. In the emergency, Leo, upheld by a
sense of his sacred office, set out to meet Attila, accompanied by Avienus, the
consul, Trigetius, the governor of the city, and a band of priests. Near where
the rivers Po and Mincio meet, they came face to face with the enemy. The Pope
reasoned with Attila and induced him to turn back.

A few years later the Vandal king, Genseric, appeared from Africa with his
army before the walls of Rome, then almost defenseless. This time Leo was able
to win from the invader only the promise to restrain his troops from arson and
carnage. After ten days of pillaging the city, the Vandals withdrew, taking back
to Africa a host of captives and immense booty, but sparing the churches of St.
Peter and St. Paul. Leo now set about repairing the damage brought by the
invasion. To the Italian captives in Africa he sent priests, alms, and aid in
rebuilding their churches. He was apparently never discouraged, maintaining a
steady trust in God in the most desperate situations. His pontificate lasted for
twenty-one years, and during this time he won the veneration of rich and poor,
emperors and barbarians, clergy and laity. He died on November 10, 461, and his
body was laid in the Vatican basilica, where his tomb may still be seen.

<On the Anniversary of his Elevation to the Pontificate>

( Sermon III )

3. <The covenant of the truth therefore abides end the blessed> Peter,
persevering in the strength of the Rock, which he received, has not abandoned
the helm of the Church which he accepted. For he was ordained before the rest in
such a manner that as he was called the Rock, as he was declared the foundation,
as he was constituted doorkeeper of the kingdom of Heaven, as he was appointed
judge to bind and loose, whose judgments will retain their validity in Heaven,
by all these mystical titles we might perceive the nature of his relationship to
Christ.

And today he still more fully and effectually performs the office entrusted
to him and carries out every part of his duty and his charge in Him and with Him
by whom he was glorified. So if any act or decree of ours is righteous, if we
obtain anything by our daily supplications from God's mercy, it is his work and
his merits, whose power lives in his see and whose authority is so high. For,
dearly beloved, his confession won this reward, his confession inspired by God
the Father in the apostle's heart, which transcended all the uncertainty of
human judgment and was endowed with the firmness of a rock that no assault could
shake. Throughout the Church Peter still says daily: "Thou art the Christ,
the Son of the living God," and every tongue which confesses the Lord is
inspired by the leadership of his voice....

4. And so, dearly beloved, with reasonable obedience, we celebrate today's
festival in such a way that in my humble person he may be recognized and
honored, on whom rests the care of all the shepherds, as well as the charge of
the sheep commended to him. His dignity is not diminished by even so unworthy an
heir. Hence the presence of my venerable brethren and fellow priests, as much
desired and valued by me, will be still more sacred and precious if they will
transfer the chief honor of this service, in which they have deigned to take
part, to him whom they know to be not only the patron of this see but also the
primate of all bishops. When therefore we utter our exhortations in your ears,
holy brethren, believe that he is speaking whose representative we are, because
it is his warning that we give and nothing but his teaching that we preach

<Letter to Flavian, Called the> Tome

3. Without detriment, therefore, to the properties of either nature and
substance (the divine and the human), which then came together in one person,
majesty took on humility, strength weakness, eternity mortality, and for the
payment of the debt belonging to our condition inviolable nature was united with
suffering nature, so that, as suited the needs of our case, one and the same
Mediator between God and men, the Man Jesus Christ, could both die with the one
and not die with the other. Thus in the whole and perfect nature of true man was
true God born, complete in what was his own, complete in what was ours....

4. There enters then these lower parts of the world the Son of God,
descending from his heavenly home and yet not quitting His Father's glory,
begotten in a new order by a new birthing. In a new order, because being
invisible in His own nature, He became visible in ours, and He whom nothing
could contain was content to be contained. Abiding before all time, He began to
be in time; the Lord of all things He obscured His immeasurable majesty and took
on Him the form of a servant. Being God who cannot suffer, He did not disdain to
be man that can and, immortal as He is, to subject Himself to the laws of death.
The Lord assumed His mother's nature without faultiness, nor in the Lord Jesus
Christ, born of the Virgin's womb, does the marvel of His birth make his nature
unlike ours. For He who is true God is also true man, and in this union there is
no deceit, since the humility of manhood and the loftiness of the Godhead both
meet there. For as God is not changed by the showing of pity, so man is not
swallowed up in the dignity.... To be hungry and thirsty, to be weary and to
sleep is clearly human, but to satisfy five thousand men with five loaves, to
bestow on the woman of Samaria living water, draughts of which can secure the
drinker from thirsting ever again, to walk upon the surface of the water with
feet that do not sink and to quell the risings of the waves by rebuking the
winds is without any doubt divine. Just as also-to pass over many other
instances-it is not part of the same nature to be moved to tears of pity for a
dead friend and, when the stone that closed the four-days grave was removed, to
raise that same friend to life with a voice of command; or to hang on the cross,
and to turn day into night to make all the elements tremble; or to be pierced
with nails and then to open the gates of paradise to the robber's faith. So it
is not part of the same nature to say: "I and the Father are one," and
to say: "The Father is greater than I."! For although in the Lord
Jesus Christ God and man is one person, yet the source of the degradation which
is shared by both is one, and the source of the glory which is shared by both is
another. For his manhood, which is less than the Father, comes from our side;
His Godhead, which is equal to the Father, comes from the Father.

(<Letters and Sermons of Leo the Great. Select Library of Nicene and
Post-Nicene Fathers>, Series II.)

1 Cyril, archbishop of Alexandria from 412 to 444, was a zealot for
orthodoxy, who, the pagans said, incited his monks to kilt the Platonic
philosopher Hypatia, when she was lecturing in his city. Cassian, a recluse and
theologian, founded the monastery of St. Victor, near Marseilles.

2 Nestorius, bishop of Constantinople from 428 to 431, taught a doctrine of
the humanity of Christ, according to which God the divine Son and Jesus the Man
were always two distinct persons; Jesus alone was born of woman, and as a man of
surpassing goodness became the dwelling place of the Word, which was incarnate
in him. The Catholic doctrine is that God and man is one Christ, one person in
two natures. In 431 Nestorius was deposed and excommunicated by the Council of
Ephesus, under the influence of Cyril of Alexandria and Pope Celestine. He and
his followers withdrew to the East, where in time they formed many communities,
spreading as far as India and the borders of China.

3 For the Manichaeans, see above, <St. Augustine>, n. I.

Saint Leo the Great. Celebration of Feast Day is April 11. Taken from
"Lives of Saints", Published by John J. Crawley & Co., Inc.